And in the defense industry, these elements are needed for night vision goggles and hard coatings.

"That turns it into a national security issue," said Benson. "That's one of reasons there's a lot of funding for this."

Globally, rare earth elements make up a $7 trillion market and support $500 billion to $600 billion in other industries.

"So it's huge," Benson said. "The challenge that we have is we don't produce any in the U.S."

Ever since an ore operation in Mountain Pass, Calif., shut down, the U.S. has been 100 percent dependent on imports, mostly from China, which controls 85 to 90 percent of the world's supply of rare earth elements.

The problem with this was brought to light in 2011, when China threatened to curtail shipments. The price of europium shot from $500 to $600 per kilogram to $3,000 per kilogram.

"And that's pretty typical of other rare earth elements, too," said Mike Holmes, vice president of research and development for the Lignite Energy Council.

Holmes said California production stopped when the cost of refining became too much. The ore in Mountain Pass was dominated by light rare earth elements, like cerium, that aren't worth as much as the heavy rare earth elements, so the expense didn't pencil out.

In China, they have an abundance of heavy rare earth elements and it's easier for the country to extract and concentrate them.

"There's a lot of work going on to come up with environmentally benign ways to recover and purify rare earth elements," said Benson, with industry looking for cheaper and easier technologies.

They're also looking for resources like China has. There are currently 12 to 15 projects across the country. In Appalachia, there's a project moving into the next phase, scaling up its technology. A demonstration project to determine whether money could be made would be the next step.

In North Dakota, 60 million-year-old volcanic eruptions and the associated volcanic ash led to a concentration of rare earth elements in the state — both light and heavy.

That's where the Lignite Research Council steps in. In addition to traditional use of coal for power, the council funds research projects that find value in lignite coal.

Holmes said this concentration of rare earth elements causes people to think about coal as a precious resource rather than a dirty source of energy.

"There are things in coal worth quite bit of money," he said, and in the process of extracting those elements, power companies can clean up their coal by removing impurities, like sodium, calcium and sulfur, before burning it for energy.

The LRC just funded $280,000 of a phase two, benchscale project in the lab at EERC. Industry chipped in $400,000 and the Department of Energy is spending $2.75 million.

"Right now we've just been doing stuff in beakers," Benson said.

If you were to walk into the EERC lab, you would see a mechanism to grind the coal, vessels that stir and mix it with a solvent, and a process to separate out the liquid to bring the elements into ore quality — one step away from refining.

Should this 18-month project work out as planned, a pilot project would be three to five years away. A small plant would process 2.5 tons per day but the next scale for North Dakota would be 10 to 20 kilograms per hour.

The emphasis so far in North Dakota has been on how to extract the the rare earth elements extracts. The state must also do more to evaluate their distribution within the coal supply.

"We need to know the extent of the resource," Holmes said, because so far there have only been a few samples taken. Without a large concentration the project wouldn't be feasible commercially.

There is currently a proposal being weighed that would map out, via a geological survey, where the rare earth elements are in the state.

The rare earth element resource in China is expected to run out in 15 years. After that the country will have to look for a new resource, which may be more expensive to mine. So U.S. researchers have until then to try to come up with their own viable solution.

Because research is in the relatively early stages, the costs are lower, Holmes said. A pilot project could cost anywhere between $15 million and $25 million, depending on scale.

"I think there is a push for it," Holmes said, despite proposals from the Trump administration to slash federal budgets. "It's a security issue."